1). Field of the Invention
This invention relates to a method of treating an electroless plating waste.
2). Discussion of Related Art
Plating techniques are often used to plate a layer of metal on a substrate such as a semiconductor wafer. Electroplating requires that a voltage be applied to a conductive metal layer on the substrate. Electroless plating has the advantage that such a layer often does not have to be formed, and that it does not require the additional apparatus to apply a voltage to any such layer.
Electroless plating solutions, however, include a reducing agent which reduces the metal in the solution so that the metal plates out over the surface of the substrate, typically in the presence of a catalyst. The electroless plating solution is eventually dispersed in a drain as waste. The ability for the reducing agent to reduce the metal is problematic in the electroless plating waste that results from the electroless plating solution. The reducing agent continues to reduce the metal over time, which produces a powder that can block waste drains. It may also be possible that the metal will plate out over surfaces within such waste drains. Hazardous gases such as hydrogen gas can also be generated in the electroless plating waste due to reducing agent oxidation, hydrolysis, etc.